Cylinder head and manifold arrangement for injected engine

ABSTRACT

A cylinder head, air intake manifold, fuel injector and fuel rail arrangement for an overhead valve engine that provides a compact assembly. The fuel rail is attached to the cylinder head by fasteners that extend parallel to the fasteners that fix the intake manifold to an adjacent portion of the cylinder head. The layout is such, however, that there is no interference between the various components and thus accessibility is improved while cost is minimized.

BACKGROUND OF THE INVENTION

This invention relates to an injected internal combustion engine andmore particularly to an air manifold and fuel rail mounting arrangementfor such engine.

The use of fuel injection in place of carburetors is being widelyaccepted in most applications for internal combustion engines. Oneconvenient and relatively low-cost type of injection system employs whatis referred to as “manifold injection.” With this type of arrangement,fuel is injected into the induction system preferably at a point quiteclose to the intake port of the engine.

With four-cycle engines, this generally means that the fuel injector ismounted in the cylinder head and injects fuel into the intake passage ata point that is located close to the intake valve seat and may, in fact,be directed directly toward that valve seat. This generally means thatthe fuel injector is mounted quite close to the area of attachment ofthe intake manifold to the cylinder head. This gives rise to certainproblems in connection with the mounting of the various components tothe cylinder head to ensure against interference between the variousmounting arrangements.

It is, therefore, a principal object of this invention to provide animproved mounting arrangement for the components of a fuel injected,internal combustion engine.

It is a further object of this invention to provide an improved mountingarrangement for the components of a manifold injected engine where thefuel injectors spray into the cylinder head intake passages.

Frequently, it has been the practice to supply the fuel to the fuelinjectors through a device that is referred to as a “fuel rail.” A fuelrail is actually a form of manifold that delivers fuel from a highpressure source to the individual fuel injectors. Many times, it hasbeen the practice to mount the fuel rail directly to the injectors andnot attach it permanently to any component of the engine other thanthrough its hydraulic connections to the fuel supply system. However,this can give rise to the likelihood or possibility of the fuel railworking itself loose, particularly if the engine is subjected tovibrations in use.

It has, therefore, been proposed to fasten the fuel manifold or fuelrail also to the engine body on which the fuel injectors are mounted.This obviously gives rise to further problems in connection withattachment of the components including the fuel rail.

It is, therefore, a further object of this invention to provide animproved arrangement for attaching a fuel rail to an engine.

It is a still further object of this invention to provide an improvedmounting arrangement for the fuel rail of a manifold injected enginewhere the fuel rail is mounted in close proximity to the intake manifoldattachment to the cylinder head.

Because of the fact that the fuel injectors are disposed generally at anangle to the portion of the intake passage which they intersect, inorder to provide the desired flow direction, then the normal positioningof the fuel rail is such that its hold-down fasteners extend at adifferent angle to the associated surface of the cylinder head than thefasteners that hold the intake manifold in place. This requiressequential machining operations and adds to the cost of manufacturingthe various cylinder head assembly.

It is, therefore, a still further object of this invention to provide animproved arrangement for holding down the fuel rail and intake manifoldto a cylinder head of an engine wherein the threaded fasteners for eachcan extend along parallel axis to simplify machining.

SUMMARY OF THE INVENTION

This invention is adapted to be embodied in a fuel injected internalcombustion engine that is comprised of a cylinder head having aplurality of intake passages. An air intake manifold is attached to thecylinder head and supplies air to the intake passages of the cylinderhead. A plurality of fuel injectors are mounted in the cylinder head andare positioned in proximity to the intake passages for spraying fueldirectly into the intake passages. A fuel rail supplies fuel to thesefuel injectors. The fuel rail is affixed to the cylinder head inproximity to the air intake manifold. The fuel rail is connected to thecylinder head by threaded fasteners that are disposed in the areabetween the fuel injector and the intake manifold so that the threadedfasteners for the fuel rail do not interfere with the attachment of theintake manifold to the cylinder head.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an end elevational view of the cylinder head and attachedcomponents of an internal combustion engine, with portions broken a wayand shown in section.

FIG. 2 is a top plan view of the components shown in FIG. 1 but with thecamshaft, cam cover and valve mechanism removed from the cylinder head.

FIG. 3 is an enlarged cross-sectional view taken along a plane parallelto the plane of FIG. 1 that passes through the axis of one of thecylinder bores of the engine.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In the drawings, an internal combustion engine constructed in accordancewith an embodiment of the invention is shown in part and is indicatedgenerally by the reference numeral 11. The engine 11 includes a cylinderhead assembly 12 to which an air intake manifold assembly, indicatedgenerally by the reference numeral 13 is affixed in a suitable manner.In addition, a fuel injection system, indicated generally by thereference numeral 14, is affixed to the cylinder head assembly 12adjacent the intake manifold 13 for injecting fuel into the inductionsystem of the engine 12.

Since the invention relates primarily to the relationship of thecylinder head, air intake manifold assembly 13 and fuel injection system14, an illustration of the cylinder block, crankshaft and other internalportions of the engine below the cylinder head assembly 12 is notbelieved to be necessary to permit those skilled in the art to practicethe invention. Where any components of the overall engine 11 are notillustrated or described, any conventional or known structure may beemployed.

The cylinder head assembly 12 is comprised of a main cylinder headcasting 15 which may be cast from aluminum or aluminum alloy or anyother suitable material. This casting 15 is formed in its lower facewith recesses 16 (FIG. 3) that cooperate with the associated cylinderbores of the cylinder block and the pistons that reciprocate therein toform the combustion chamber to the engine 11.

In the illustrated embodiment, the engine 11 is depicted as being of afour-cylinder inline type. It will be readily apparent to those skilledin the art, however, that the invention can be employed with engineshaving any number of cylinders and any desired cylinder arrangement suchas V-type engines or the like.

The combustion chamber recesses 16 are formed in a planar lower surface17 of the cylinder block casting 15 which surface is held in sealingarrangement with the associated cylinder block via threaded fastenersthat pass through fastener receiving openings 18 formed in the cylinderhead casting 15 in spaced relationship around the combustion chamberrecesses 16.

The cylinder head casting 15 is formed on one side (the right hand sidein the illustrated embodiment) with an intake passage arrangement,indicated generally by the reference numeral 19. In the specific exampleillustrated, the intake passage arrangement 19 is of the Siamese typefor each cylinder having a common inlet opening 21 in an externalsurface 22 of the cylinder head casting 15. This passage arrangement 19divides into a pair of passage portions 23, each of which terminates ata respective valve seat 24 in the cylinder head combustion chamberrecess 16. These valve seats 24 may be formed in any suitable manner, asby pressed or bonded seat inserts 25.

Intake valves, which appear only partially in FIG. 3 and whichreciprocate about an axes 26 that lie in a common plane control theopening and closing of the intake valve seats 24. These intake valvesare operated by a suitable mechanism, namely an overhead mounted intakecamshaft 27 that has beating portions 28 that are journaled in bearingsurfaces 29 machined directly in the cylinder head casting 15. Bearingcaps (not shown) are affixed to the cylinder head casting 15 by means ofthreaded fasteners that are received in tapped openings 31 formed onopposite sides of the bearing portions 29 as may be seen in FIGS. 2 and3. As seen in FIG. 3, the rotational axis of the intake camshaft 28 isindicated at Ia in FIG. 2. The valve axis line 26 intersects this axis.

Spark plugs (not shown) are mounted within spark plug wells 32 formed inthe central portion of the cylinder head casting 15 and which define anaxis 33 along which the received spark plug extends. This axis 33 isintersects substantially the center of the combustion chamber recess 16.Thus, a spark plug received therein will have its gap disposed in thisarea so as to ensure complete charge burning throughout the entirety ofeach combustion chamber.

A pair of exhaust valve seats 34 are formed in each cylinder head recess16 and form the inlets to exhaust passages 35 which extend therefrom tooutlet openings in an exterior surface 36 of the cylinder head casting15. Like the intake passages 19, the exhaust passages 35 for eachcylinder are Siamesed. The exhaust valve seats 34 are formed, like theintake valve seats 24, by suitable inserts 37 that are attached to thecylinder head casting 15 in a suitable manner.

Poppet type exhaust valves, which are not shown, are mounted in thecylinder head casting 15 in a suitable manner and reciprocate alongrespective exhaust valve axes 38. These exhaust valve axes 38 lie in acommon plane that is disposed at an acute angle α to plane containingthe intake valve axes 26.

The exhaust valves are operated by an exhaust camshaft 39 which isjournaled in bearing surfaces 41 formed in the upper surface of thecylinder head casting 15. The exhaust camshaft 39 has bearing portions42 that are journaled in the surfaces 41 and which are retained in placeby bearing caps (not shown). These bearing caps are affixed to thecylinder head casting 15 by threaded fasteners that are threaded intotapped openings 43 formed in the cylinder head casting 15.

The intake camshaft 27 and exhaust camshaft 39 are driven by a suitabletiming mechanism such as a chain, which is shown schematically in FIG. 2and which is indicated by the reference numeral 44. The exhaust camshaftrotational axis is indicated by the broken lines Ea in this Figure.

The intake camshaft 27 has cam lobes 45 that cooperate with thimbletappets (not shown) slidably supported within bores 46 formed in thecylinder head casting 15 for operating the intake valves in a well knownmanner. In a like manner, the exhaust camshaft 39 has cam lobes 47 thatcooperate with thimble tappets (also not shown) received in bores 48formed in the cylinder head casting 15. As has been previously noted,the valve actuating mechanism may be of any known type and the foregoingdescription is merely exemplary.

Between the spark plug wells 32 at each end of the engine, there areprovided a pair of clean-out openings 49 in the cylinder head casting15. This is to permit removal of core sand. These openings 49 are thenclosed by freeze plug as is well known in this art.

The valve actuating mechanism described is enclosed by a cam cover 51that is affixed in a suitable manner to the cylinder head casting 15.

The induction manifold 13 is served by an air inlet device which is notshown but which communicates with a throttle body 52 through an airsupply duct 53. The throttle body 53 contains one or more throttlevalves that are operated remotely by the operator and which control theflow of air into a longitudinally extending plenum device 54.

The plenum device 54 extends along one side of the engine and has aplurality of runner sections 55 emanating from it, one for each intakepassage opening 21. The runners 55 have a re-entrant curvature andterminate at their discharge ends in respective flange portions 56 thathave a pair of lugs that receive threaded fasteners 57. These fasteners57 are threaded into tapped openings 58 formed in the cylinder headcasting 15 on opposite sides of the openings 21 of the intake passages19. These tapped openings 58 extend perpendicularly to the cylinder headsurface 22.

The intake manifold 13 and its attachment to the cylinder head castingas thus far described may be considered to be conventional. Theinvention deals primarily with the fuel supply system 14 and its mannerof attachment to the cylinder head casting 15 and its relationship tothe induction system and specifically the flanges 56 of the manifoldrunners 55 and their attachment to the cylinder head surface 22. Thisstructure will be described now.

It has been noted that the intake passages 19 are Siamesed. At a pointwhere the passages merge upstream of the valve seats 26, there isprovided a recess 59 in the cylinder head. A fuel injector nozzleportion 61 extend into this recess and sprays along a flow axis Sadirected generally in a downstream direction and toward the intake valveseats 24.

The fuel injector nozzle 61 forms a main portion of a fuel injectorassembly 62 that is received within an injector opening 63 that ismachined into a surface 64 of the cylinder head casting 15. This surface64 is slightly offset from but parallel to the surface 22 to which themanifold flanges 56 are affixed.

The fuel injectors 62 are of the electrically operated type and have anactuating solenoid that is provided with a terminal 65 to which a wireharness (not shown) is affixed so as to control the timing of openingand closing of the injector valves thereof

A fuel supply system supplies fuel to the fuel receiving nozzles of theinjector 62 and this includes a main fuel rail 66. This main fuel rail66 has complementary sealed openings that interconnect with the fuelreceiving portions of the injector 62 so as to provide a leak-proof fuelsupply thereto.

Fuel is delivered from a remote fuel tank through a pressure conduit 67as best seen in FIG. 2. This pressure conduit 67 extends to the forwardor cam drive end of the engine where it is connected to a banjo fitting68. The banjo fitting 68 supplies fuel to a central flow passage 69 ofthe main fuel rail 66.

The opposite end of the main fuel rail 66 mounts a pressure regulator 69which regulates pressure by dumping excess fuel back to the remote fueltank through a return line 71. In order to ensure that the injected fuelis at a pressure that is at a fixed amount above the pressure of the airinto which it is injected, the pressure regulator 69 has a portion 72that receives air at the pressure in the plenum chamber 54 through aconduit 73. Hence, the pressure of the fuel injected is alwaysmaintained at a fixed value above the pressure of the air into which itis injected.

A pair of angularly shaped mounting bracket 74 are affixed to one sideof the main fuel rail 66 in the area between adjacent injectors andbetween the manifold runners 55 as best seen in FIG. 2. These mountingbrackets 74 may be formed from a non-metallic material such as aresinous plastic or the like. They are affixed to the main fuel valve 66by threaded fasteners 75. The other leg of these brackets 74 engages acircular non-metallic washer 76 that is interposed between this bracketleg and the cylinder head surface 54.

Threaded fasteners 77 are passed into tapped openings 78 formed in thecylinder head casting 15. The fuel rail 66 is formed with a pair ofreliefs 79 adjacent the heads of the fasteners 77 so as to facilitatetheir access.

It should be noted that the cylinder head casting has a portion 81 thatextends inwardly toward the head bolt opening 18. These tapped openings78 extend into this portion but do not penetrate it. This projection 81is such that it will not obscure the access to the head of the fastenerwhich affixes the cylinder head casting 15 to the cylinder block andwhich engages a machined surface 82 formed on the upper side of the camchamber portion of the cylinder head casting 15.

Because the axes of the tapped openings 78 is parallel to the axis ofthe tapped opening 58 that receives the manifold fasteners 57, machiningis simplified and can be done with a gang drill. Also, it should benoted that the axes of the fasteners 77, indicated at 83 in FIG. 3, areparallel to the axes 84 of the manifold runner 55 and the inlet portionof the intake passages 19. Thus, setup time is facilitated also withthis arrangement.

Thus, from the foregoing description, it should be readily apparent thatthe described cylinder head construction permits the attachment of theintake manifold and the fuel rail in close proximity to each otherwithout interference and in such a manner as to simplify machining. Ofcourse, the foregoing description is that of a preferred embodiment ofthe invention and various changes and modifications may be made withoutdeparting from the spirit and scope of the invention, as defined by theappended claims.

What is claimed is:
 1. A fuel injected internal combustion enginecomprised of a cylinder head having a plurality of intake passages, anair intake manifold attached to said cylinder head for supplying air tosaid cylinder head intake passages, a plurality of fuel injectorsmounted in said cylinder head and positioned in proximity to said intakepassages for spraying fuel directly into said intake passages, and afuel rail for supplying fuel to said fuel injectors, said fuel railbeing affixed to said cylinder head in proximity to said air intakemanifold, said fuel rail being connected to said cylinder head bythreaded fasteners that are disposed in the area between said fuelinjectors and said air intake manifold so that said threaded fastenersfor said fuel rail do not interfere with the attachment of said intakemanifold to said cylinder head.
 2. A fuel injected internal combustionengine as set forth in claim 1 wherein the threaded fasteners foraffixing the fuel rail to the cylinder head are disposed at a differentangle to a supporting surface of the cylinder head than the axis of thefuel injector.
 3. A fuel injected internal combustion engine as setforth in claim 2 wherein the angle of the threaded fasteners to thecylinder head surface is inclined toward the intake manifold relative tothe axis of the fuel injector.
 4. A fuel injected internal combustionengine as set forth in claim 3 wherein the threaded fasteners areperpendicular to the cylinder head surface and the axis of the fuelinjector is inclined away from the intake manifold.
 5. A fuel injectedinternal combustion engine as set forth in claim 2 wherein the threadedfasteners are parallel to the axes of the intake passages.
 6. A fuelinjected internal combustion engine as set forth in claim 1 wherein thefuel rail is affixed to the cylinder head by at least one angularlyshaped bracket having a first leg affixed to one side of said fuel railand a second leg which cooperates with the threaded fasteners foraffixing said bracket to said cylinder head.
 7. A fuel injected internalcombustion engine as set forth in claim 1 wherein the fuel rail isaffixed to a cylinder head surface that is juxtaposed to andsubstantially parallel with the surface of the cylinder head to whichthe air intake manifold is attached.
 8. A fuel injected internalcombustion engine as set forth in claim 7 wherein the threaded fastenersfor affixing the fuel rail to the cylinder head are disposed at adifferent angle to the cylinder head surface than the axis of the fuelinjector.
 9. A fuel injected internal combustion engine as set forth inclaim 8 wherein the angle of the threaded fasteners to the cylinder headsurface is inclined toward the intake manifold relative to the axis ofthe fuel injector.
 10. A fuel injected internal combustion engine as setforth in claim 9 wherein the threaded fasteners are perpendicular to thecylinder head surface and the axis of the fuel injector is inclined awayfrom the intake manifold.
 11. A fuel injected internal combustion engineas set forth in claim 7 wherein the threaded fasteners are parallel tothe axes of the intake passages.
 12. A fuel injected internal combustionengine as set forth in claim 11 wherein the fuel rail is affixed to thecylinder head by at least one angularly shaped bracket having a firstleg affixed to one side of said fuel rail and a second leg whichcooperates with the threaded fasteners for affixing said bracket to saidcylinder head.
 13. A fuel injected internal combustion engine as setforth in claim 1, further including a camshaft journaled in the cylinderhead and juxtaposed to the fuel rail so that the fuel rail is disposedbetween the air intake manifold and the camshaft.
 14. A fuel injectedinternal combustion engine as set forth in claim 13, wherein thethreaded fasteners are received in tapped openings formed in a wall ofthe cylinder head, said wall being juxtaposed to but spaced transverselyoutwardly from a surface of said cylinder head that is engaged by afurther threaded fastener for affixing said cylinder head to anassociated engine body.
 15. A fuel injected internal combustion engineas set forth in claim 1, wherein the threaded fasteners are received intapped openings formed in a wall of the cylinder head, said wall beingjuxtaposed to but spaced transversely outwardly from a surface of saidcylinder head that is engaged by a further threaded fastener foraffixing said cylinder head to an associated engine body.